Neurotensin is a peptide produced in brain and gut of many animal species, including man. This peptide is released into blood, particularly after a lipid meal. Since many patients notice anginal pain after meals we tested the effect of neurotensin on coronary blood flow, cardiac function and metabolism. Thus, in dogs when we infused neurotensin directly into the coronary artery we noted a reduction in coronary blood flow of about 30% and associated with an impairment of left ventricular contractile function, and the development of acidosis in the myocardium. These findings indicate that neurotensin is capable of causing coronary vasoconstriction and severe functional consequences of left ventricular dysfunction and ischemic acidosis.